Polycarbonate resins produced from bisphenol A and the like have been finding use in materials for various parts in, for example, an electrical and electronic field and an automobile field because the resins are excellent in thermal resistance and mechanical properties. However, sliding properties may be requested of the resins depending on places where the resins are used. In addition, a polycarbonate resin formed of bisphenol A is poor in sliding property when being used alone. Accordingly, the addition of a sliding property improver has been attempted. For example, a resin composition with polytetrafluoroethylene (PTFE) (see Patent Document 1), a resin composition with a silicone oil (see Patent Document 2), a resin composition with a polyolefin wax or the like (see Patent Document 3), and a resin composition with a polyphenylene resin (see Patent Document 4) have been known as polycarbonate resin compositions for sliding use.
When a sliding property material is added in a small amount to any one of those resin compositions, an improving effect on the sliding property of the resin composition is insufficient. However, increasing the addition amount involves the emergence of the following problem. That is, mechanical properties such as tensile property inherent in a polycarbonate resin reduce, or the sliding property reduces owing to wear or dropping upon long-term use.
Meanwhile, a polycarbonate-polydimethylsiloxane copolymer (PC-PDMS) has been known as a polycarbonate excellent in impact resistance and flame retardancy (see Patent Document 5).
However, only a small number of reports have been made on the sliding property of the PC-PDMS itself and the sliding property has not been satisfactory (see Patent Documents 6 to 9). Accordingly, in actuality, it has been necessary to blend PTFE as a sliding property improver into the PC-PDMS to prepare a resin composition (see Patent Document 10).
It has been recently reported that a polycarbonate resin obtained by the polycondensation of an acryl-denatured polyorganosiloxane having a hydroxyl group, a diol compound, and a carbonic acid derivative has improved sliding property and is suitable for an electrophotographic photosensitive member. However, only the molecular weight of the produced acryl-denatured polyorganosiloxane-copolymerized polycarbonate has been described, and no information about the copolymerization amount and siloxane chain length of the polycarbonate has been given (see Patent Document 11).
It has been reported that a copolymer having a terminal denatured with polyorganosiloxane is excellent in sliding property after a weatherability test (see Patent Document 12) and has a reducing effect on a coefficient of dynamic friction (see Patent Document 13).
That is, it has been necessary to improve the sliding property in any polycarbonate resin.    Patent Document 1: JP 7-228763 A    Patent Document 2: JP 36-7641 B    Patent Document 3: JP 2005-320367 A    Patent Document 4: JP 2007-23094 A    Patent Document 5: JP 2663210 B2    Patent Document 6: JP 05-202181 A    Patent Document 7: JP 05-202182 A    Patent Document 8: JP 05-200761 A    Patent Document 9: JP 05-200827 A    Patent Document 10: JP 04-225061 A    Patent Document 11: JP 2006-16566 A    Patent Document 12: JP 2002-284871 A    Patent Document 13: JP 2008-102196 A